Boiler



A. HUET May 8, 1934.

BOILER Filed Sept. 16, 1931 3 Sheets-Sheet l ATTORNEYS.

A. HUET May 8, 1934.

BOILER Filed Sept. 16, 1931 3 Sheets-Sheet 2 INVENTOR.

ATTORNEYS.

' May 8, 1934. A. HUET 1,957,536

BOILER Filed Sept. 16, 1931 3 Sheets-Sheet 3 1 IN V EN TOR.

24 By a/ A TTORNEYS.

Patented May 8, 1934 UN iT BOILER Andre Huet, Paris, France, assignor to The Superheater Company, New York, N. Y.

Application September 15, 1931, Serial No. 563,121 In France November 14, 1930 1 Claim.

The present invention has for its object a method of transforming an existing boiler of low or medium pressure into a boiler of high pressure without requiring a large expenditure of money, as well as the arrangement resulting from such method.

This method of transforming such a boiler consists essentially in adding first a high pressure feed-water heating drum containing a condenser tube bundle ied by steam produced in the existing boiler and secondly a primary closed heating circuit and a high pressure evaporation drum traversed. by said circuit.

In this manner the existing boiler serves to produce low pressure steam or steam of medium pressure in a primary closed circuit comprising the condensing tube bundle mentioned above. This steam gives its latent heat of vaporization to feed water which is to produce the service steam. In the economizer the water is heated as nearly as possible to the saturation temperature corresponding to the pressure under which it is desired to produce the service steam. It then passes into the evaporating drum but before doing so may be carried through a further feedwater heater. Such further feed-water heater may be of the indirectly heated type with a primary closed circuit or of any other desired type able to give the water a temperature equal to the saturation temperature of the high-pressure boiler. In the evaporation drum the condensing part of the second primary closed circuit is immersed, its vaporizing portion being heated by the furnace gases, this furnace ordinarily being the original boiler furnace.

The following description given by way of eX- ample in connection with the accompanying drawings will make clear in what manner the invention may be carried out.

Fig. 1 represents the application of the invention to an existing water tube boiler, the furnace of the latter being utilized. Fig. 2 shows the application of the invention to a boiler of the same type, a new furnace being added. Figs. 3 and 4 show respectively a transverse and longitudinal section of the fire-box of a locomotive boiler modified in accordance with the invention. Fig. 5 is a longitudinal section of an assembly of such a locomotive boiler on a smaller scale. Figs. 6 and '7 illustrate two different applications of the invention to a marine boiler.

The boiler shown in Fig. 1 is an existing boiler of low or medium pressure in which the water tubes 2 are secured to the headers 3 which in turn communicate with the cylindrical drum 1 by tubes 4.

To transform this boiler into a high pressure steam generator there has been added among other things an economizer drum 5 enclosing a condensing tube bundle 6. The tube connections 7 carry steam produced in the cylindrical drum 1 to this tube bundle where it is condensed giving up its latent heat of vaporization to the feed water which is brought in by the tube connections 9 from a feed pump (not shown in the drawings).

The condensate formed in the tube bundle 6 is carried back to the drum 1 by the tube connections 8.

Under the tubes 2 is mounted the vaporizing bundle of tubes 10 of a primary closed circuit comprising also a steam riser 11, a condenser bundle of tubes 12 arranged in a vaporizing drum 14 and return tube 13 by which the condensate from the tube bundle 12 is carried back to the vaporizing tube bundle 10.

In the example shown the vaporizing bundle 10 is placed in the furnace of the existing boiler where it forms one or several water walls and may form a partial or total arch. 30

The water heated in the economizer drum 5 and brought in this drum to a temperature as near as possible to the saturation temperature corresponding to the pressure existing in the drums 14 and 5 passes into the drum 14' by the tubing 15. In this drum it is vaporized by the heat given to it by the steam enclosed in the condenser bundle 12 while this steam condenses. The steam formed passes by the pipe 16 to the place of steam consumption passing if desired through a superheater (not shown) which may be located in the boiler housing.

Thanks to the high temperature to which the water is raised in the drum 5 the impurities which it contains are there precipitated, but on account of the slight temperature diiference existing between this water and the steam contained in the condenser tube bundle 6, this precipitation occurs in the form of a soft mud which can be removed either periodically or continually through the blow-off 17. The water will therefore be purified before it reaches the drum 14 and this drum will therefore not become scaled In Fig. 2, the low pressure or medium pressure 0 boiler shown, is analogous to that of Fig. 1 and all the parts corresponding to parts in Fig. 1 have been given the same reference number. The vaporizing bundle 10 is located in a special furnace 18 adjacent to the former furnace. The

hot gases coming from the furnace 18 pass over a superheater 19 through which flows the steam coming from the conduit 16 through the header 20. These hot gases then pass into what was formerly the boiler furnace and thence travel to the stack after having come in contact with the tube bundle 2 of the former boiler.

In Figs. 3, 4 and 5, the parts corresponding to those of Figs. 1 and 2 bear the same reference numerals, but the boiler 21 is a locomotive boiler with smoke tubes and the vaporizing tube bundle 10 is located in the furnace of such boiler, its tubes lining either all or a part of the walls of the fire box although it may be placed at any other convenient point.

It will be noted that the dome at present generally used on locomotive boilers may be omitted since there is no longer any danger of turbulent ebullition and consequent water entrainment by steam flowing to the conduit 16 connected to the saturated steam header 20 of the superheater.

In Fig. 6, the invention is applied to a marine boiler 22, the vaporizing tube bundle 10 being located in the combustion chamber 23.

In the case of Fig. '7, the application to this same boiler is made by placing the vaporizing tube bundle 10 in the combustion chamber 24.

It will be noted that in certain of the forms shown the addition of the new vaporizing tube bundle results in a reduction of the dimensions of the grate, of the furnace, or of the combustion chamber or of several of them; but since high pressure steam is to be generated in place of low pressure or medium pressure steam for which the furnace was originally designed, this reduction does not result in any reduction of the power of the engine.

It goes without saying that modifications in the details may be made to these devices which have just been described without departing from the spirit of the invention.

What I claim is:

The combination of a horizontal return tube boiler having an internal fire box and combustion chamber, a bundle of generating water tubes within said boiler at a point in the path of the heating gases from said fire box prior to the return tubes, a relatively high pressure steam generating drum containing a condensing coil connected to receive steam from said water tubes and to return condensate thereto, a non-generating economizer drum having a heating coil therein connected to receive steam from said return tube boiler and to return condensate thereto, a connection between said drums for conducting water from the latter to the former drum and for maintaining the pressures therein equal, and means for forcing water through said economizer drum into the other said drum.

ANDRE HUET. 

